1. Field of the Invention
The present invention relates to a screw rotor mechanism for use in screw compressors or the like, and more particularly to a pair of asymmetrically toothed male and female rotors each having teeth of a specific profile adapted to be machined by a gear hobbing machine by which machining at an increased rate during its manufacturing is achieved
2. Description of the Prior Art
A screw compressor was originally invented by Krigar in Germany in about 1878 and ever since various improvements have been made in this connection. In place of the so-called symmetrically toothed rotors which were used in the original screw compressor, SRM (Svenska Rotor Maskiner Aktiebolag) of Sweden introduced in 1965 asymmetrically toothed rotors with markedly improved volumetric efficiency. An example of the asymmetrically toothed rotors can be seen, for instance, in U.S. Pat. No. 3,423,017. Such rotors of the asymmetrical teeth have been progressively improved in recent times. The applicant of the present invention has also invented a rotor mechanism which is disclosed in U.S. Pat. No. 4583927, as schematically shown in FIG. 5 of the accompanying drawings.
The rotors of FIG. 5 were improvements over earlier rotors in having achieved an increase of a theoretical volume thereof. The male and fomale rotors, designated at reference numerals M,F, respectively, have respective teeth shaped with the following characteristics.